Helios
A high-energy upper stage that rides on another company's rocket and pushes heavy satellites from low Earth orbit to geostationary orbit in under a day, or toward the Moon.
Why it matters
Most rockets can lift far more mass to low orbit than to geostationary orbit. Helios lets a medium-lift rocket deliver satellites to their final high orbit in under a day, skipping months of slow climbing, and the Space Force has added it to its national security launch pool.
How the technology works
Helios is a kick stage that rides on a medium-lift rocket. Its Deneb engine burns liquid methane and liquid oxygen and makes about 67 kN of thrust.
Impulse says it can carry more than 5 tons from low Earth orbit to geostationary orbit in less than a day. SES has signed a multi-launch agreement, with the first mission planned for 2027, and Impulse lists first flight for 2027.